[April 03, 2014]SPRINGFIELD — The Illinois
Department of Natural Resources Division of Fisheries is receiving
reports of fish kills on lakes and ponds around the state. Dead fish
have become apparent as ice cover thaws. IDNR biologists emphasize
that occasional fish kills are natural and occur when light cannot
penetrate ice, slowing the growth of algae and plants that produce
oxygen. It is often difficult to determine the full extent of a
winter fish kill since not all fish killed may be visible. As a
result, many pond owners are seeking additional information on the
cause, and advice on restocking after a winter fish kill.

Shallow ponds are
more likely to have been affected. Deeper ponds initially have a
greater volume of oxygen and are more likely to sustain fish.
But even some of these ponds are experiencing winter kills.

Ponds that have
experienced winter fish kills in the past are likely to have
done so again this winter.

In many cases, the
last spawn of bluegill (up to 1 inch long) can survive the low
oxygen levels. Pond owners should assume all bass have died and
restock as soon as possible.

Even if some bass survive, it is easier
to correct an overpopulation of bass than an overpopulation of
bluegill.

IDNR county biologists can provide proper stocking advice for
your specific pond, especially if species are present other than
what is listed below.

General stocking guidelines for the
smallest fish available are as follows:

Largemouth bass: 50
per acre

Redear sunfish: 300
per acre

Bluegill: 250 per
acre

Channel catfish:
40-100 per acre (optional)

Fathead minnows:
about 5 pounds per acre.

Fall follow-up:

Larger bluegill (3
to 5 inches long) can be stocked in the fall if the pond owner
wants to wait to see if bluegill survived.

It is important to
follow up in spring 2015 with another 50 bass per acre, but the
larger size (5 to 7 inches long) should be stocked then.

If bass fry
are not observed in summer of 2015, it may be wise to stock
another 50 per acre in spring 2016 — again, the larger size.

Redear sunfish
may not do well in northern Illinois, where pumpkinseed
sunfish are the ecological equivalent.

Grass carp
should only be restocked if vegetation was a problem
previously. Crappie or hybrid sunfish should not be
restocked without consulting your county fish biologist for
suitability or timing of the restocking.